Set Square Suggestions

[Damienol]

Hi WWF

I need a pair of plastic set squares to align my fence for my TableSaw supersled. Can anyone recommend some cheapies that are square?

[Twisted Tenon]

If it's big plastic squares you need, you could probably get them from Office Works.
I have one of these (http://www.carbatec.com.au/veritas-poly-gauge_c3790) and find it really useful.

TT

[Damienol]

If it's big plastic squares you need, you could probably get them from Office Works.
I have one of these (http://www.carbatec.com.au/veritas-poly-gauge_c3790) and find it really useful.

TT

That is what I was considering however I am concerned with the accuracy. $3 plastic set square is a long way ( in price) from a $150 starrett combination square

[Twisted Tenon]

Fair enough. I use a couple of plastic squares made by "Kent", got them from a graphics arts store years ago. I used them with a drawing board. They were probably around $20.00 - $30.00 per set and very square. I looked at the Starrett stuff last year and it is true and square. To me it's the sort of stuff you would use to build a bench top on a space station :rolleyes:.

TT

[elanjacobs]

+1 for Starrett. There are always plenty on eBay second hand. I picked up a 12" No. 20 master precision square (accurate to 0.0001" per 6" or 0.00167%) for around $180 shipped from the US (RRP is over US$600)

If you're on a budget and aren't working on the next space station, the Irwin squares are well and truly good enough at 0.01% tolerance.

[FenceFurniture]

I use the 12" version of the Woodpeckers Triangles (http://www.woodpeck.com/carpentertriangles.html), and find it excellent as it will stand on the thick edge. Problem is that they did their last run a few months ago.

[derekcohen]

A cheap $3 plastic drafting square from the local newsagent will probably be as accurate as anything else out there.

To reassure yourself, do the "draw a perpendicular line-flip square- draw another perpendicular line" test. That will tell you if it is a square square.

Regards from Perth

Derek

[Twisted Tenon]

What about those yellow roofing triangles? They are square and have a flat side that sits nicely on the saw table.

TT

[IanW]

A cheap $3 plastic drafting square from the local newsagent will probably be as accurate as anything else out there.


Someone wrote about plastic squares in a mag I read years ago. They found the cheapest plastic squares to be highly accurate.

Setting a saw blade with the most accurate set-square in the world may not get you perfectly square cuts. The square may be perfect, but it is exceedingly difficult to get that blade aligned dead-on. For starters, many blade plates are not machined parallel, & those protruding carbide teeth get in your way!. In any case, setting a static blade may not give you a square cut, due to the pre-tensioning of the blade (they should be slightly dished when static), and any run-out (particularly likely on less-expensive saws) doesn't help your cause, so all your square's precision may be wasted.

You really should be checking the actual cut edge, & the simplest way to do that is to use a variation of Derek's scribe & flip method for checking a square: Grab a length of waste that has parallel sides, set you saw to an indicated 90, and cut, with one of those sides down. Flip the offcut 180 degrees & match to the other side of the cut, with both sitting flat on the saw table. If the cut ends align perfectly, all is well. If not, make the necessary adjustments 'til they do. Or, simply check the cut edge with a trysquare, as you do for the rest of the dimensioning process - it's plenty accurate enough for 99% of situations.

Cheers,

[dalejw]

I quite like the Nobex Octo's (I've got 3 sizes). Accurate to 0.05º and folding but I agree with Ian. You've gotta start cutting stuff to work out if everything is square.

[Damienol]

For context I am building this SuperSled. http://www.eaglelakewoodworking.com/post/Super-Sled-Crosscut-and-Miter-Sled.aspxOne of the final steps involves a pair of drafting squares to square the rear fence to the blade. Hence the post.I purchased a pair of empire rafter squares however they are faaaaaaaar from square.

[artme]

I had not managed to find my set squares, that I had had since I was 12 and used for Tech Drawing at high school,
when I needed to square up some stuff here, including my saw blade. I went to a local cabinet maker and he cut me
a couple of melamine coated pieces of 5/8 particle board on his saw. These were as square as anything I have used
because I checked them with a flip test. Solid and perfectly suited to the job..:)

[NCArcher]

Watch this video and do the 5 cut test at the end for super squareness :2tsup:
http://www.thewoodwhisperer.com/videos/the-cross-cut-sled/

[FenceFurniture]

Another great vid from the Wood Whisperer. Thanks for posting.

[chambezio]

You do know you can make your own squares?
I found that a plastic square set used for drawing were a bit to small in stature to accurately set out a,say table sized job. (This came from my kitchen manufacturing days.) To get a perfect 90° get a piece of suitably sized sheet of MDF (or what ever you have at hand) then use a largish pair of compasses and swing an arc from your base line and draw a half circle. Now open the compasses to any distance which is greater than the radius you have drawn. Put the compass point on the point of intersection where the arc meets your straight line. Swing another arc back and over the original point Then repeat from the other straightline and arcpoint. This will give you a point directly over the centre mark of the arc. Now just mark a line from the centre point of the original half circle and the new point where the arcs meet and there you have a perfect 90° line off your starting point/straight line.


Its a whole lot easier to do than to write "how"

I made a 45° 45° as well as a 60° 30°. They are around 550mm long and are about the same size as the ones we used in high school

Edited to add; The Egyptians figured this method out one day when it rained and they had to "stop play" when they were contemplating building a stone BBQ for the Pharaoh. You know what happen when a committee designs something (Yeh it turned into a Pyramid)